This project was initiated to identify and characterize the biochemical basis of receptor mechanisms for biogenic amines in mammalian CNS. From the knowledge obtained about dopamine receptors, it is possible to begin to formulate mechanisms of action for drugs used in the treatment of Parkinson's disease. Among the topics pursued in the current fiscal year were: 1) studies to classify the properties of the presynaptic dopaminergic autoreceptor; 2) A clarification of the functional role of dopamine in the mammalian striatum utilizing a modification of the 2-deoxyglucose technique; 3) The identification of a beta-adrenergic receptor in mammalian brain which regulates adenylate cyclase in cell-free homogenates; 4) Utilizing the dopamine-sensitive adenylate cyclase and the beta-adrenergic receptor regulating this enzyme, the factors responsible for the coupling of adrenergic receptor to adenylate cyclase were identified; 5) The preparation of a review of the biochemistry and physiology of dopamine receptors in mammalian tissues; and the proposal that multiple classes of dopamine receptors exist.